diagnostics property

The first node is typically an ErrorSummary giving a short description
of the problem, suitable for an index of errors, a log, etc.

Subsequent nodes should give information specific to this error. Typically
these will be ErrorDescriptions or ErrorHints, but they could be other
objects also. For instance, an error relating to a timer could include a
stack trace of when the timer was scheduled using the
DiagnosticsStackTrace class.